In the dental art, it is known to recover amalgam and heavier metal particles flowing in a stream formed of flushing liquid and debris by passing the liquid stream through relatively complicated sump structures, as shown in the U.S. patents to Mitchell, U.S. Pat. No. 3,305,927, issued Feb. 28, 1967; Ritche, U.S. Pat. No. 3,777,403, issued Dec. 11, 1973; and Ritzler, 3,870,483, issued Mar. 11, 1975. These devices are designed to receive the liquid stream of flushing water and the usual mixture of debris from the dentists' activities, including washing water, tartar scraped from the teeth, tooth particles, cotton and gauze fibers, blood clots, buffing compounds, ground off tooth swarf, broken fillings, including particles of amalgam, saliva and other debris removed from the mouth during the performance of dental work on a patient. While such known sump structure may serve more or less efficiently to separate amalgam from a flow of flushing liquid, they cannot be easily disassembled for cleaning and sterilization when it is necessary to recover the accumulated amalgam and to prepare the sump for further use.
A device making use of a riffle structure for the recovery of precious metal from the flow in natural streams is illustrated in the U.S. Patent to Craft et al, No. 2,926,786, issued Mar. 1, 1960. Such a device, while embodied in a relatively simple structure, does not provide a means that can be sterilized or easily adapted to wholly contain a waste flow from a dental operation. The open sluice-type structure, shown in this patent, is not intended to wholly contain a fluid flow containing matrial to be separated from the flow, and thus would not provide a sterile device adapted for use in a confined space, such as a dentist's office or the like.